The present invention relates to the production and use of hydrogen onboard a marine vessel and, more particularly, to systems and methods to convert water supplied to a vessel into hydrogen (H2) for later use as an energy carrier for vessel power or propulsion.
Presently, the vast majority of marine vessels use onboard fossil fuel engines, such as diesel, fuel oil or gasoline for power and propulsion. These onboard fossil fuel propulsive systems and electrical generators are large sources of both air and water pollution. Existing fossil fuel technologies also generate noise pollution, vibrations and foul smells. Further, fuel quality and bacterial growth are problems for users of diesel and fuel oils, while explosions from trapped vapors concern operators of gasoline systems.
A need has arisen, therefore, for the development of alternative fuels which reduce or eliminate some of the problems associated with fossil-fuel technologies. There exist known technologies for reducing pollution, vibration and noise in land based vehicles, such as the use of gasoline or diesel-electric hybrid power systems, battery and fuel cell electric drives, metal hydride storage technologies, compressed natural gas, methanol, and hydrogen burning internal combustion engines. For example, a gas-hybrid system, in which H2 is added to the fuel/air intake system or combustion chamber of a fossil fuel engine prior to combustion, can reduce polluting emissions. It is also known that a fuel cell power system consuming H2 stored in a metal hydride tank can provide safe (relative to fire and explosion hazards), ecologically xe2x80x9ccleanxe2x80x9d power.
However, while many developments in the xe2x80x9calternativexe2x80x9d fuels industry are aimed at land based transportation systems, which reduce or eliminate some of the above referenced problems in land vehicles, these same technologies and systems show great promise for adaptation to the marine environment. For example, it is known that the most energy efficient, vibration free and quiet method of propelling a large marine vessel is via an electric motor. One additional advantage of some electric motors is that they may also be used as a generator to produce electrical energy. For example, on some gas turbine powered aircraft the starter motor reverts to a generator once the gas turbine engine has started.
For all of these systems, however, the single most significant obstacle facing implementation, with the exception of the gasoline-fueled hybrid, is the absence of a national retail xe2x80x9calternativexe2x80x9d fueling infrastructure. Developing such an infrastructure would require a multi-billion dollar, decade-long commitment, and even with the advent of gasoline-fueled hybrids, the danger posed by explosion of vapors and the non-renewable nature of gasoline result in a less than optimum long term solution.
Thus, a further need has developed for a system which would reduce the polluting effects of fossil-fuel engines in maritime vessels, while also eliminating the need for a new refueling infrastructure. While presently it is known to desalinate and otherwise purify ocean or fresh water through reverse osmosis, for example, and to generate H2 from that water by electrolysis, i.e., with electrical energy, and while it is also known that the most cost-effective and environmentally benign method of electrolysis uses electricity from renewable sources, such as solar (photo voltaic or PV), wind and water drag electricity generators; and while it is also known that electrical energy suitable for use in onboard electrolysis is also available from engine and auxiliary and shore power sources, these technologies have never been assembled onboard a marine vessel in such a way as to provide a ready source of energy for electrical power or propulsion without the need for the creation of a new external infrastructure.
Briefly, the present invention is directed to a system and method for producing and utilizing H2 entirely onboard marine vessels eliminating the need for new refueling infrastructure.
In one embodiment, the system utilizes the H2 produced by the invention as an energy carrier for propulsion and non-propulsion power requirements. In this system, H2O is obtained from the sea or other water source and then conducted to an onboard water purification device. The purified H2O is then converted via any efficient H2O to H2 conversion device into hydrogen (H2) and oxygen. The gaseous H2 produced is either used directly by the onboard power plant(s) or stored.
In another embodiment, a method is provided so that the system may use electricity for H2O to H2 conversion and other invention processes (e.g., water purification) from multiple renewable and non-renewable sources.
In another embodiment of the invention, the system eliminates the trapped vapor explosion danger of gasoline fueled power and propulsion systems by using solid state metal hydride tanking technologies for H2 storage whenever possible.
In another illustrative embodiment of the present invention a system is provided to improve the efficiency of the system by recycling fuel cell waste heat and condensation of steam exhaust for re-use by the electrolysis components.
In yet another embodiment the invention is directed to a method for the production and utilization of H2 onboard a marine vessel utilizing the systems described above.
Preferred examples of certain advantageous embodiments of the processes in accordance with the present invention are set forth in the accompanying illustrations and tables together with preferred embodiments of the specific elements of this invention required to properly carry out this invention.
In the illustrations and tables and in the following text describing the process and embodiments, the elements of the apparatus and the general features of the procedures are shown and described in relatively simplified and generally symbolic manner. Appropriate structural details and parameters for actual operation are available and known to those skilled in the art with respect to the conventional aspects of the process.